Made this cable myself and selling it off at parts' cost for US$25. The cable itself is made out of silver plated copper wires with MMCX connectors on one end and straight 2.5mm balanced plug on the other. Total length is about 50cm and it is meant to be used with BT adapter with balanced output, such as the EarStudio ES100 or A&K XB10. Shipping is either (1) US$10 for snail mail without tracking or (2) US$40 for EMS with international tracking. I accept Paypal only and can ship anywhere but Israel.